Heat recoverable closure assembly

ABSTRACT

A closure assembly consisting of a container and a closure member wherein the container has a heat recoverable portion which cooperates with said closure member to close and seal said assembly. A flange is provided on the closure member which is wider than a corresponding groove on the container. The groove is defined by heat recoverable material and is presented in an expanded state. The closure member may then be heated and inserted in the groove causing the heat recoverable material to shrink about the flange to provide positive closure of the assembly. An adhesive may be incorporated within the groove to further seal the assembly. The closure member most conveniently is a material having a high thermal conductivity to enhance the heating of the heat recoverable material.

United States Patent [1 1 Evans et al.

[4 Oct. 7, 1975 HEAT RECOVERABLE CLOSURE ASSEMBLY [73] Assignee: N. V.Raychem S.A., Kessel-lo,

Belgium [22] Filed: May 31, 1974 [30] Foreign Application Priority DataJune 6, 1973 United Kingdom 26176/73 52] us. Cl. 220/33; 174/50Q220/354;220/359 51 Int. cm B6'5D 43/02 [58 Field of Search 220/3.8, 354, 359;

FOREIGN PATENTS OR APPLICATIONS 1,193,129 5/1965 Germany ..220/3.81,389,544 l/l965 France ..220/3.8

Primary Examiner-William 1. Price Assistant ExaminerStephen MarcusAttorney, Agent, or Firm-Lyon & Lyon [57] ABSTRACT A closure assemblyconsisting of a container and a closure member wherein the container hasa heat recoverable portion which cooperates with said closure member toclose and seal said assembly. A flange is provided on the closure memberwhich is wider than a corresponding groove on the container. The grooveis defined by heat recoverable material and is presented in an expandedstate. The closure member may then be heated and inserted in the groovecausing the heat recoverable material to shrink about the flange toprovide positive closure of the assembly. An adhesive may beincorporated within the groove to further seal the assembly. The closuremember most conveniently is a material having a high thermalconductivity to enhance the heating of the heat recoverable material.

11 Claims, 4 Drawing Figures HEAT RECOVERABLE CLOSURE ASSEMBLY Thisinvention relates to heat recoverable closure assemblies, especially tocontainers having a heat recoverable portion cooperating with a closuremember such as a top or clamp.

It is known to provide closure assemblies incorporat-. ing a containerand a closure member such as a top or clamp wherein a flange and groovearrangement is provided between the closure member and the container.The flange and groove in such assemblies generally has an interferencefit or other conventional arrangement whereby a seal or resistance toopening is achieved. However, in many applications. it is impractical toprovide such a juncture because of difficulties in fabrication, inassembly and in maintaining integrity of the seal. Further, quite oftensuch systems are incapable of being rcentered and then re-closed.

One such application where a waterproof box is required which can laterbe re-entered and then re-sealed is for junction boxes used in cabletelevision systems. The junction boxes must be re-enterable in order toattach a further cable for supply to a new subscriber after the systemhas been laid under ground. Junction boxes for this purpose typicallyhave an orifice, usually with a flange. for the input line and a similarorifice for each output line. Like junction boxes used elsewhere in theelectronics industry, the boxes are typically rectangular having a flatlid through which the box may be entered for inspection or servicing.

In the past, such junction boxes have been made of many materials. forexample, aluminum or polyethylene. More recently polyethylene has becomepopular to allow the flanges around the orifices to be made heatrecoverable so that sealing of the overlap between the box and the cablecan be facilitated. The internal surfaces of the flanges are coveredwith mastics or hot melt adhesives. Orifices which are not in use can beplugged or formed with a readily removable end cap so that a newsubscribers line can be easily fitted.

It will be apparent that sealing against ingress of moisture, boththrough the overlap between the orifices and the cables and through thejoint between the box and the lid is a necessary feature when the box isto be used outdoors, especially underground.

Similarly, certain underground cable assemblies must provide a closureassembly that can be easily reentered and then closed again and stillprovide a seal capable of preventing moisture intrusion intothe cablesor other easily damaged components. It has likewise become desired andoften beneficial to employ polyethylene or other plastic material in theform of cylindrical containers for such cables. However, it is normallynecessary to cut the container in order to reenter the conduit. Thus, itis necessary to re-assemble a container about the conduit after servicehas been completed.

The present invention provides a means for providing a scalablecontainer which may be easily re-entcred. It is also possible to resealthe container at a later time. To accomplish this. a container isprovided with a heat -recoverable portion about the opening therein. Acloconductivity. In this way. the groove may be expanded and held inthat state before the flange associated with the closure member isplaced on the container. The flange may then be heated and positioned inthe groove, thus resulting in a shrinking of the groove about the flangeto create a sealed container.

Accordingly, it is an object of the present invention to provide animproved closure assembly.

It is another object of the present invention to provide an improvedprocess for securely enclosing a container.

it is a further object of the present invention to provide a closureassembly employing heat recoverable material for securely closing theassembly.

Moreover, an object of the present invention is to provide a waterproofjunction box capable of being reentered and closed.

It is yet another object of the present invention to provide acylindrical container for conduits which may be re-entered through anapplication of heat.

Other and further objects and advantages will appear hereinafter.

FIG. 1 is a perspective exploded view of a box and top according to thepresent invention.

FIG. 2 is a fragmentary section through a side wall and part of the topof FIG. 1.

FIG. 3 is a cross-sectional view of a conduit employing an enclosuremember according to the present invention.

FIG. 4 is a fragmentary exploded section showing the closure of FIG. 3.

Referring now to the drawings, specifically FIGS. 1 and 2, a containeror box, generally designated 1, includes a base 2, and side wall 3. Thebox is designed for incorporation as a junction box for cable televisionsystems or other electrical systems and includes a plurality of flangedapertures 4 through which cables may extend to various receivinglocations. The container 1 is made of a thermoplastic material which ismost conveniently of a type having heat recoverable properties.Alternately, it is only necessary that the upper portion of each sidewall is of a heat recoverable nature. The heat recoverable material ofthe box is preferably a cross-linked thermoplastic material, forexample, one specified in British Pat. No. 990,235. The box may beformed, for example, by molding. Cross-linking may be achieved by any ofthe known methods, for example, by the use of chemical cross-linkingagents.

The free end of the side walls, as best seen in FIG. 2, is in the formof a generally U-shaped cavity or groove 5. The groove 5 may bepartially filled with a hot melt adhesive 6. The grooves extendcompletely about the opening or aperture formed in the box as is definedby the free ends of the side walls 3. Thus, a seal may be achievedcompletely about the opening as will be seen below.

A closure member or top 7 is provided as a means for closing the openingin the upper portion of the container l. The closure member 7 includes aflange 8 extending downwardly from the lower surface thereof about theouter edge of the closure member 7. This flange 8 is substantially thesame shape and dimension as the corresponding groove 5 located in thecontainer 1. However, the width of the flange 8 is larger than the widthof the groove 5 when the heat-recoverable material forming the groovesis in a heat-stable state. The closure member is relatively rigid and isof a material which will remain rigid at the recovery temperature of theheat recoverable material of the container. Further, as will bediscussed below, the closure member 7 is preferably of a material havinga high thermo conductivity, such as brass.

To prepare the container 1 for assembly,.the groove 5 and the.immediately surrounding area of the container l is heated to atemperature where the heat recoverable material is in a dimensionallyheat-unstable state. .ln this condition, the groove 5 is expanded andheld in the expanded position. While being held in the expandedposition, the container 7.and groove 5 are cooledthereby causing thegroove 5 to remain in the expanded state. Once the components areestablished within the container 1, the closure member 7 may be heated.Once heated, the closure member is pressed onto the top of the container1 so that the flange 8 is positioned within the groove 5. The heat fromthe closure member 7 is then quickly transferred to the heat recoverymaterial defining the groove 5 causing it to shrink to its originalconfiguration and thereby securely hold and seal the closure member.

Where a hot melt, adhesive 6 is employed in the groove 5, a further bondis provided thereby. The heated closure member7 will cause the hot meltadhesive 6 to melt during the recovery of the heat recoverable material.Consequently, the heat recoverable material forming the groove 5 willclose about the flange 8 and also spread or squeeze the hot meltadhesive 6 about the flange 8 to form a tight joint between thecontainer 1 and the closure member 7.

Thus, using the art and process of the invention as applied to the firstembodiment, the portion of the container l that needs to be heated tocause recovery may be raised to the appropriate temperature withoutheating .the' remainder of the container 1 to any great extent. lngeneral, it isundesirable to subject the remainder of-the container 1 toheating. Also, because of the low thermoconductivity of thermoplastics,the present invention allows heat to be applied only where it is needed.By properly choosing a closure member 7, for example a metal top of highthermoconductivity, there is also achieved the advantage that when thecontainer 1 needs to be reopened, all that is necessary is the top 7 tobe heated again. Heat is then conducted through the flange 8 to thoseportions of the container which needs to be reheated to release the top.Where there is hot melt adhesive, this is softened and in all cases therecoverable portion receives sufficient heat to begin to reach recoverytemperature before heat is transferred to the remainder of thecontainer. If the closure member 7 is then pried loose from thecontainer, the heat source is immediately removed from the groove 5.With care, recovery can be averted before it is complete. Thus, thegroove 5 is left in a partially recovered state so that the closuremember 7 can be readily replaced as desired. ln-any case, even ifrecovery is complete, the use of a rigid metal top 7 enables therecoverable-portion of the container 1 to be reopened on reheatingsimply by pressure applied to the top 7. This is. of course, facilitatedby having the flange 8 tapered. Once again, when the closure member 7and groove 5 cool, the container 1 is again rescaled.

Turning to the second embodiment, as shown in FIGS. 3 and 4 of thedrawing, a container 9 is formed in a sheet like arrangement having twomating edges 10 and 11 formed at opposite ends of the sheet. A raisedportion 12 is provided adjacent either edge 10 and 11 to furtherstrengthen the container member 9. A 010- sure member 13 formed into achannel member including two flanges l4 and l5-which may be positionedin grooves 16 and 17. The grooves 16 and 17 are positioned in raisedportions 12 and typically extend the length of the sheet. Hot meltadhesives 18 may also be provided.

To assembly this second embodiment, the container member 9 is flexed toplace the two mating edges 10 and 11 in abutting relationship to closethe opening there between. Thegrooves 16 and 17, having been previouslyexpanded through the process described above, are then positioned toreceive the closure member l3. Thelclosure .member 13 is heated and thenplaced with the container 9 so that the flanges l4 and 16 are positionedinthe corresponding grooves 16 and 17. The grooves 16 and 17 then shrinkabout the flanges l4and 15 respectively as the entire assembly cools.Thus, a second closure member is provided to open this secondembodiment, the closure member'l3 is again heated and easily withdrawnfrom the container 9. The container 9 may then be unwrapped from aboutthe cables, splices or other components contained therein.

Thus, apparatus and procedure is provided for erecting a closureassembly which is advantageous for applications where a positive seal isrequired. Further, by heating the closure member, the assembly may beeasily opened and later closed. While embodiments and applications ofthis invention have been shown and described, it would be apparent tothose skilled in the art that many more modifications are possiblewithout departing from the inventive concepts herein described. Theinvention, therefore, is not to be restricted except by the spirit ofthe appended claims.

What is claimed is:

l. A heat recoverable closure assembly comprising:

a container, said container including an opening into said container anda groove adjacent .said opening, said groove being defined by heatrecoverable material; and

a closure member of high thermal conductivity, said closure memberincluding a flange capable of coextensive arrangement with said groove,said flange being wider than said groove when said groove is in its heatstable state.

2. The heat recoverable closure assembly of claim 1 wherein said openingconstitutes a substantially fixed aperture and said groove extends aboutsaid aperture.

3. The heat recoverable closure assembly of claim 1 wherein saidcontainer comprises a. sheet extending to two mating edges, said sheetbeing capable of being flexibly arranged to place said two mating edgesin abutting relationship, said groove extending adjacent each of saidtwo mating edges to receive said closure member.

4. The heat recoverable closure assembly of .claim 1 wherein adhesive isprovided within said groove.

5. The heat recoverable closure assembly of claim 1 wherein said closuremember is metallic.

6. The heat recoverable closure assembly of claim 1 wherein saidcontainer comprises a sheet extending to two mating edges, said matingedges defining said opening and being flexibly arranged in abuttingrelationship, said groove extending adjacent each of said two matingedges to receive said closure member.

wherein said top is metallic.

9. The heat recoverable closure assembly of claim 7 wherein saidcontainer is capable of providing a subterranean junction box forelectrical components.

10. The heat recoverable closure assembly of claim 7 further comprisingadhesive placed within said groove.

11. The heat recoverable closure assembly of claim 10 wherein saidadhesive is a hot melt adhesive.

1. A heat recoverable closure assembly comprising: a container, saidcontainer including an opening into said container and a groove adjacentsaid opening, said groove being defined by heat recoverable material;and a closure member of high thermal conductivity, said closure memberincluding a flange capable of coextensive arrangement with said groove,said flange being wider than said groove when said groove is in its heatstable state.
 2. The heat recoverable closure assembly of claim 1wherein said opening constitutes a substantially fixed aperture and saidgroove extends about said aperture.
 3. The heat recoverable closureassembly of claim 1 wherein said container comprises a sheet extendingto two mating edges, said sheet being capable of being flexibly arrangedto place said two mating edges in abutting relationship, said grooveextending adjacent each of said two mating edges to receive said closuremember.
 4. The heat recoverable closure assembly of claim 1 whereinadhesive is provided within said groove.
 5. The heat recoverable closureassembly of claim 1 wherein said closure member is metallic.
 6. The heatrecoverable closure assembly of claim 1 wherein said container comprisesa sheet extending to two mating edges, said mating edges defining saidopening and being flexibly arranged in abutting relationship, saidgroove extending adjacent each of said two mating edges to receive saidclosure member.
 7. A heat recoverable closure assembly comprising: acontainer, said container including an access aperture and a groove insaid container extending about said aperture, said groove being formedfrom heat recoverable material; and a top of high thermal conductivity,said top including a flange capable of co-extensive arrangement withsaid groove, said flange being wider than said groove when said grooveis in said heat stable state.
 8. The heat recoverable closure assemblyof claim 7 wherein said top is metallic.
 9. The heat recoverable closureassembly of claim 7 wherein said container is capable of providing asubterranean junction box for electrical components.
 10. The heatrecoverable closure assembly of claim 7 further comprising adhesiveplaced within said groove.
 11. The heat recoverable closure assembly ofclaim 10 wherein said adhesive is a hot melt adhesive.